Untargeted metabolomics reveals key steroidal glycoalkaloids and associated metabolites in crude and C18-purified extracts of potato leaves

Potato leaves are an abundant by-product of potato production. Although they contain steroidal glycoalkaloids (SGAs) and other bioactive metabolites, the chemical composition of SGA-enriched leaf extracts and the impact of purification steps remains insufficiently described. Here, we aimed to profile and compare a crude SGA-enriched extract and a C18 solid-phase extraction (SPE)-purified fraction obtained from potato leaves. LC–MS/MS-based untargeted metabolomics annotated 1,761 metabolites across the two extracts, including terpenoids (6.94%), alkaloids (4.90%), and steroids (1.22%). The dominant SGAs were solanidine, α-chaconine, and α-solanine. After data filtering for statistical analysis, 1,760 metabolites were retained; 800 met the differential screening criteria (VIP > 1 and |log2FC| ≥ 1) in purified extract vs. crude extract, whereas 960 did not. The metabolites most affected by C18 purification were mainly organic acids and derivatives, benzene and substituted derivatives, amino acids and derivatives, and glycerophospholipids. In contrast, the major SGAs did not meet the differential screening criteria, suggesting that C18 SPE preserved the core SGA constituents. C18 purification substantially changed a subset of polar co-extracted metabolites but largely maintained the major SGAs in potato leaf extracts. These results provide a metabolite catalog for SGA-enriched potato leaf extracts and a chemical basis for optimizing extraction and purification strategies. Further work should optimize SGA enrichment and evaluate bioactivity and safety to support potential agricultural applications.